1. Field of the Invention
This invention relates to a method of fabricating a joint between a helical wound tubular fibrous composite and a metal ring and more particularly to the self-locking effect between the metal ring and fibrous composite overlay which forces the helical wound fibers to fail before separation of the ring and composite can occur.
2. Description of the Prior Art
Methods of making a joint between a tubular filament wound composite and a metal flange have used a long taper joint as in a clamp joint or various combinations using adhesive bonding or bolted fasteners. With these conventional methods the joint is usually the first area in the structure to fail. Failure may be due to failure of the adhesive or fasteners or due to premature failuare of the composite itself because of stress concentrations. Ideally the joint securing arrangement should result in the composite and metal flange acting as one monolithic unit and attaining the full strength capability inherent in the materials used.
U.S. Pat. No. 4,118,262 describes a method of forming filament wound reinforced tubular composites and how to attach them to rings utilizing pins to transfer the load from the component to the ring. Since the pins are cured into the rigid structure the assembly is rigid and conforms to the shape in which it was cured. Load redistribution in the joint is impaired. Therefore, it is desirable, and it is another object of this invention to provide an arrangement where stress concentrations are minimized and load redistribution is free to occur when local deformation results.
U.S. Pat. Nos. 4,265,951; 4,097,626; 4,236,386; 4,385,644; 4,256,412; and, 4,238,540 show joints between composites and metallic parts, but none utilize the joint construction disclosed herein.
While the method for making conventional joints between tubular filament wound composites and a metal flange have been satisfactory for smaller structures, such arrangements are not completely desirable for large structures subject to relatively large forces both static and dynamic. Due to the multiplicity of operations in the forming of these prior art arrangements, they are both laborious and time-consuming to construct. In addition, the ability of these arrangements to support load is highly dependent upon the ability and consistency of the person forming the joint. Therefore, it is also desirable, and it is still another object of this invention to provide a joint which is capable of high loadings, simple to construct and free of workmanship dependent limitations.